Geosynchronous satellites are relied upon as part of larger communication networks by businesses, universities and individuals to provide a wide variety of communication services. Because a single satellite in geosynchronous orbit may transmit to a large portion of the Earth's surface, satellites are ideal for providing communication services to remote or thinly populated areas where cabling (e.g., land line, fiber optics, etc.) would not be economically feasible, or where rights-of-way would not easily be established. Satellites therefore allow advanced communication services to be made available around the world. For example, satellite systems are well suited for providing geographically distributed media services, such as video broadcasting.
Recently, it has been proposed to use a constellation of low-Earth orbit (LEO) satellites to provide telecommunications services to the entire world. In a LEO system, signals are transmitted from a first Earth-based terminal to a satellite on an up-link, routed through the constellation, and then transmitted from the satellite to a second Earth-based terminal on a down-link. The satellites therefore act as nodes in a network through which the signals are routed. The information carried in the signals may be generically referred to herein as "data," and may include audio, video, or other types of data.
Many LEO systems have proposed routing data through the constellation in the form of "data packets." At the first Earth-based terminal, the data to be transmitted is divided into multiple data packets that are routed through the satellite constellation and then reassembled at the destination Earth-based terminal to reconstitute the original data. In systems that packetize data for transmission, each data packet may take an independent route through the constellation from the source Earth-based terminal to the destination Earth-based terminal. If network traffic is light, data packets are quickly routed through the communication system. Sometimes, however, the satellite communication network may become congested due to equipment failures or particularly heavy data packet traffic, for example. Congestion could slow delivery of data packet traffic, and impact the timeliness of traffic required for near real-time applications, such as videoconferencing. It can be appreciated, therefore, that there is a significant need for techniques that reduce congestion within a LEO satellite communication system. The present invention provides this and other advantages as will be illustrated by the following description and accompanying figures.